CA 2.0, Tire clearances and wheels sizes.

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There have been some questions about the new CA 2.0 wheel, tire clearance and brake reach. I’ll try and clear those up here.

The 650c  (that is 571 mm ) rear end CA 2.0 has 11mm clearance between a 23 mm x 571mm tire and the frame,

Good range of brake pad travels allows two wheel sizes!
Good range of brake pad travels allows two wheel sizes!



Short reach brakes like the Zero-G will reach the 650c (571mm) rim with no problems.

You can put a 559 (26” rim) in the frame and with the Bacchetta rear brake it reaches the rim no problem, room to spare. Put a 26 x 1.25” (32mm) like a Kenda Qwest you have 6mm clearance between frame and tire.

Even with a 26 x 1.25" (32mm) you have clearence of 6mm!
Even with a 26 x 1.25




Bacchetta rear brake reaches the 559 rim, sweet!
Bacchetta rear brake reaches the 559 rim, sweet!


The 700c (620mm) CA 2.0) current proto-type rear end with a 700c x 23mm tire gives you 6mm clearance between the tire and the frame. The Zero-G short reach brakes fits with no problems and it looks like we could add 3mm more of length to the chain stay to gives us some possible options of getting a 28mm tire into the 700c rear end.

Looks like the CA 2.0 is going to be a great all around bike, I can envision many uses of this bike from hard core racing to light touring and of course doing the full brevet series.

Keep spinning

John Schlitter


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12 responses to “CA 2.0, Tire clearances and wheels sizes.”

  1. Since you mentioned light touring and brevets, what’s the chance of getting clearance for fenders? I’m thinking that if the frame was designed for medium reach sidepulls (i.e. 49-59 mm reach, I think), then it would be possible to slip some skinny fenders in there.

    Or is the fork the limiting factor for this?

    Steve K.

  2. John, thanks for taking the measurements and photos. Why not give the 622 version 11 mm clearance like the 571 version has? That way both frames could run all the same brakes and the 622 frame would just barely have clearance for a 32-622 tyre. To give maximum clearance but still be able to use a Zero Gravity rear brake how about making the chainstay length such that a Zero Gravity brake will work on both versions with the pads set as low as they will go.

  3. It looks loke you need to add AT LEAST 5mm to the chain stays of the 700c version to make this a well designed frame. The major issue for most of us waiting around for the CA frame in 700c is to have some tire sizr flexability. We tall guys, who are most likely to be comfortable on on 700c wheels, are also typically heavier and are looking for the ability to use 700×25 racing tires and 700×28 brevit tires… without this flexability your new design CA 2.0 will be for naught.

  4. Steve, on the 650c CA 2.0 even with a 26 x 1.25″ tire (559 rim) you have 6mm clearence which might alow a thin fender to go on. I have used Planet Bike SpeedEz strap on fenders on tight clearence frames with good success. Not as complete coverage as a bolt on set but you sure can take thenm on and off fast. Do remember the design mission for the CA 2.0 is a for racing! JS

    Zach, I was goig to say add 3mm plus to the 622 frame, I agree about trying to get the same clearence as the 650c (11mm) in the end th tis what I’ll be shooting for. The trick is the Zero-G’s do run 1-2 mm longer then a lot of other short reach brakes so I want to make sure I do not lose other options. JS

    dexey, sorry no disc brake option at this time, that opens another can of worms. In the future it maybe possible after a few years on the CA 2.0 frame to consider a disc brake drop out mold.

    Jim, point taken, in response to Zach pretty well covers it.

  5. Any chance the 700c version may have a rear disc brake mount. For those of us around 250 lbs, a disc brake option would be a really nice thing.

  6. Bill, on a SWB the front brake is the most important brake as you have all that weight transfer to the front wheel when braking. On the CA 2.0 you could always run a disc brake compatible front fork with a disc brake and have almost as good braking capacity as a dual disc setup. I’ve been riding a Ti Aero with an Avid BB7 160 mm front disc brake and rear sidepull brake and to keep wear off the rear rim I don’t use the rear brake at all on this bike. It is just there in case I have a front brake failure. At your weight for dealing with brake heat on a long descent that requires a lot of braking for speed control I’d either use the rear side pull brake a bit to take heat loading off the 160 mm front brake rotor or preferably use a 180 mm or 203 mm front brake rotor and still use primarily the front brake for speed control.

    That said I would still like to see a 700 carbon frame down the road that has a rear disc brake mount. That way I could run a set of fat 559 mm tyres and not have any worries about rear brake clearance being the limiting factor. Something like a Giro 26 but carbon. I guess the price of carbon frames would really have to come down to make a second disc brake model viable as most people your weight who want dual disc brakes would rather buy a Giro 26 rather than spending a lot more on a carbon frame just to save a small percentage of gross vehicle weight (rider and bike).

  7. Zach, what fork are you using with your Ti Aero? I’ve been looking for lightweight and/or aerodynamic road forks with disc mounts but I haven’t found much so far other than cyclocross and touring forks.


  8. Is the reason for no disc brakes the fact that there is a lot of torque transferred to the frame? If so, wouldn’t the new Carbon with nano-tube technology provide the additional strength without adding that much to the price?

  9. Sam, I’m using a Wound Up fork on my Ti Aero. It weighs 550 g with 310 mm carbon steerer tube which compares favourably with the stock Carbon Johnson fork which weighs 518 g with 250 mm steerer though it isn’t ultra light like the Reynolds Ouzo Pro Aero fork on my Carbon Aero I weighed at 394 g. Unfortunately the Wound Up fork has round blades so it isn’t particularly aerodynamic. If I knew of an aerodynamic, lightweight road fork with disc mounts I’d be using it.

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